Composition for assaying for nitrites

Abstract

A composition for assaying nitrites comprising a diazotizable amine, an acid component and a coupling component, wherein the coupling component is a compound of the following formula I: ##STR1## wherein R represents a hydrogen atom or a straight-chain alkyl group having 1 to 6 carbon atoms, such as a methyl, ethyl, n-propyl, n-butyl, n-pentyl or n-hexyl group and n represents an integer of 1 to 6, with the proviso that the sulfoalkyl group may be substituted with at least 1 hydroxyl group, or a water-soluble salt thereof as well as test devices carrying the composition. This composition is far more sensitive than conventional compositions for assaying nitrites. With this composition, for example, a trace amount of as small as 0.02 mg/100 ml of a nitrite to be detected in urine in the diagnosis of a bacterial infection such as urinary tract infection can be detected surely.

What is claimed is: 
     
       1. A composition for assaying for nitrites comprising a diazotizable amine, an acid component and a coupling component, wherein said coupling component comprises a compound of the following formula I: ##STR3## wherein R represents a hydrogen atom or a straight-chain alkyl group having 1 to 6 carbon atoms, and n represents an integer of 1 to 6, with the proviso that carbon atoms of the sulfoalkyl group may be substituted with at least 1 hydroxyl group, or a water-soluble salt thereof.   
     
     
       2. A composition for assaying for nitrites according to claim 1, wherein said coupling component of the formula I is a compound selected from the group consisting of: N-(1-naphthyl)-3-aminopropanesulfonic acid,   N-(2-methyl-1-naphthyl)-3-aminopropanesulfonic acid,   N-(2-ethyl-1-naphthyl)-3-aminopropanesulfonic acid,   N-(1-naphthyl)-4-aminobutanesulfonic acid,   N-(1-naphthyl)-2-aminoethanesulfonic acid, and   N-(1-naphthyl)-3-amino-2-hydroxypropanesulfonic acid.   
     
     
       3. A composition for assaying for nitrites according to claim 1, wherein said coupling component of the formula I is N-(1-naphthyl)-3-aminopropanesulfonic acid. 
     
     
       4. A composition for assaying for nitrites according to claim 1, wherein said diazotizable amine is a compound selected from the group consisting of sulfanilamide, sulfanilic acid, arsanilic acid and p-aminobenzoic acid. 
     
     
       5. A composition for assaying for nitrites according to claim 1, wherein said diazotizable amine is sulfanilamide. 
     
     
       6. A composition for assaying for nitrites according to claim 1, wherein said acid component is a compound selected from the group consisting of tartaric, citric, oxalic, malic, malonic, succinic and glutaric acids. 
     
     
       7. A composition for assaying for nitrites according to claim 1, wherein said acid component is tartaric or citric acid. 
     
     
       8. A composition for assaying for nitrites according to claim 1, wherein said diazotizable amine, said acid component and said coupling component of the formula I or a water-soluble salt of the formula I are dissolved in water or an organic solvent such as methanol or ethanol. 
     
     
       9. A test device for assaying for nitrites, comprising a composition for assaying for nitrites supported on an absorptive carrier applied to a support, wherein said composition comprises a diazotizable amine, an acid component and a coupling component, said coupling component being a compound of the following formula I: ##STR4## wherein R represents a hydrogen atom or a straight-chain alkyl group having 1 to 6 carbon atoms, and n represents an integer of 1 to 6 with the proviso that carbon atoms of the sulfoalkyl group may be substituted with at least 1 hydroxyl group, or a water-soluble salt thereof.   
     
     
       10. A test device for assaying for nitrites according to claim 9, wherein said coupling component of the formula I is N-(1-naphthyl)-3-aminopropanesulfonic acid. 
     
     
       11. A test device for assaying for nitrites according to claim 9, wherein said absorptive carrier is filter paper. 
     
     
       12. A test device for assaying for nitrites according to claim 9, wherein said support is a plastic sheet. 
     
     
       13. A process for assaying for nitrites, comprising contacting a substance to be assayed for nitrites with a composition comprising a diazotizable amine, an acid component and a coupling component, and observing a color change indicative of the presence of nitrites in said substance, wherein said coupling component comprises a compound of the following formula I: ##STR5## wherein R represents a hydrogen atom or a straight-chain alkyl group having 1 to 6 carbon atoms, and n represents an integer of 1 to 6, with the proviso that carbon atoms of the sulfoalkyl group may be substituted with at least 1 hydroxyl group, or a water-soluble salt thereof.   
     
     
       14. A process for assaying for nitrites according to claim 13, wherein said composition is supported on an absorptive carrier applied to a support.